Punctuation, one is taught, has a point: to _____1_____ law and order. Punctuation marks are the road signs _____2_____ along the highway of our communication—to control speeds, provide directions and prevent _____3_____ collisions. A period has the unblinking finality of a red light; the comma is a flashing yellow light that asks us only to slow down; and the semicolon is a stop sign that tells us to ease gradually to a halt, _____4_____ gradually starting up again.